A standard pneumatic tube transport system uses carriers each formed as a rigid sleeve whose ends are provided with collars having guide rings that ride on the inside surface of the transport tube and with at least one membrane-type annular seal engaging the tube inner surface so air pressure can move the carrier along the tube without blowing past the carrier. The carrier has one end that is closed and an opposite end that is provided with an openable cover. Such devices can be used for transporting documents, samples, or virtually any small object that must be moved through rapidly between fixed locations. The standard carrier cover displaceable pivotally between a closed position engaged over the sleeve end and an open position offset from it, normally pivoting about an axis parallel to the axis of the sleeve as described in German 297 08 204.
In a particularly common application, such a system is used in a hospital to transport blood samples, biopsy specimens, and the accompanying paperwork between the patient floors, operating theaters, and laboratories. Accordingly a carrier is described in U.S. Pat. No. 5,636,974 which splits along a plane including the sleeve axis into two halves and that can be solidly closed together. This system reduces the possible leakage of biohazards into the tubing of the transport system. It is, however, fairly complex and expensive and is mainly aimed at cushioning the contents of the carrier so that, if they do leak, the contents can get out of the carrier into the tubing system where they not only present the possibility of spreading disease, for instance a long-lived staphylococcus infection, but also can create a sticky mess that can cause the carriers to get stuck in the tube. Cleaning and disinfecting a contaminated tube is a complex job that entails considerable downtime for the critical system.
When the carriers are made particularly tight, as for instance with special closures or screw tops, they become difficult to open. The longitudinally subdivided system of above-cited U.S. Pat. No. 5,636,947 requires two hands to open and must be wholly pulled out of the tube before it can be opened. These systems are frequently setup so that when the carriers come to rest their ends merely project out of the tube docking station with the idea that the tube can be opened with one hand, something that is impossible with the prior-art tight-seal carriers.